Acids and acid solutions have long been used in the stimulation of oil wells, gas wells, water wells, and similar boreholes. Acid stimulation is performed in wells completed in subterranean formations. Acid stimulation is used in conjunction with hydraulic fracturing techniques and matrix acid stimulation techniques. In both acid fracturing and matrix acid stimulation, the well treating acid solutions, usually HCl or mixtures of HCl and HF, are pumped through the well tubular goods and injected into the formation where the acid attacks formation materials increasing its permeability to oil and/or gas.
In order to protect the equipment and tubular goods from the corrosive effects of the acid, the well treating acid almost always includes a corrosion inhibitor, frequently referred to as ACI's.
In order to extend the effectiveness of the acid corrosion inhibitors, the literature suggests the use of additives, including the metal salts of iodide and chloride as disclosed in U.S. Pat. Nos. 3,773,465; 4,871,024; 4,997,040; 3,773,465.
One of the problems encountered in using the ionizable salts is that they are not compatible with organic based corrosion inhibitor formulations. For example, it is generally understood that metal chlorides or iodide salts are not soluble in the organic liquids used in corrosion inhibitor formulations. Therefore, metal chloride or iodide salt intensifiers must be formulated separately and used in combination with organic based corrosion inhibitors. Use of these so-called “external intensifiers” therefore results in increased on-site formulation, handling, transport and application costs.